This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Allosteric communication between remote sites is a crucial element in enzymatic function. Using TROSY-based NMR spectroscopy, we will map long-range allosteric changes along the backbone of the catalytic subunit of cAMP-dependent protein kinase A (PKA) upon binding a nucleotide analogue (AMP-PNP) and the peptide LRRASLG (Kemptide) as substrates. Calculations for the binding constants of the two ligands, as well as for on and off rates will be obtained. Since the enzyme retains activity under our NMR conditions, the structural changes monitored in this study will reflect the interconversion of conformations during turnover. These studies represent a paradigm for how multidomain kinase turnover involves complex dynamics transmitted within its structure. In addition, this is the first report of monitored dynamic changes within an active kinase at atomic resolution.